The present invention relates to a bus bar for electrical power distribution having improved shape and characteristics.
More particularly, the bus bar according to the invention has a structure with a modular geometry in which the basic geometric element can be easily adopted to provide bus bars sized to carry nominal currents having different amperages; moreover, the bus bar according to the invention is unique in its simplicity both from the point of view of production and in practical use, allowing to considerably simplify assembly.
It is known that distribution switchboards for distributing electric power to a plurality of electrical devices, such as for example circuit breakers, use a system of mutually parallel bus bars.
Each one of the bars is connected to a corresponding polarity of the electric power supply mains; the connection between the bus bars and the devices is provided by means of adapted conductors, such as for example laminae, which are shaped appropriately according to the type of device.
Bus bars, according to the functions that they are required to perform in the practical application, must have a few basic characteristics; in particular, they must have a simple and functional constructive structure which allows extreme flexibility in assembly and coupling to other conducting or insulating elements. Said constructive structure must also be conceived so that it can be easily adopted to produce bars that conduct nominal currents with different amperages, without having to significantly modify the steps of the production of said bars or of the elements to which they are to be coupled.
It is also important for the bars to have a structure which on the one hand ensures the rigidity required to withstand the electrodynamic stresses produced by the flow of current during normal conduction and on the other hand allows to optimize the amount of material used in production, so as to achieve an economic benefit.
In the current state of the art, the use of conventional bus bars has drawbacks which make them less than satisfactory from the point of view of production and in practical use.
It is traditionally known to use flat bars with a solid rectangular transverse cross-section; although these bars are extremely simple from the point of view of production, they have considerable disadvantages in coupling to other elements, such as for example additional bars. Such cases in fact require bar drilling operations, which vary in each instance according to the coupling configuration to be obtained, and the adoption of particular connecting means which are appropriately shaped. An example in this regard is shown in U.S. Pat. No. 5,364,203.
It is also known in the art to use bus bars whose transverse cross-sections are shaped so as to facilitate coupling to other bars or to supporting and/or insulation elements; these elements are meant to fix the bars to supporting structures and to assist them in withstanding the electrodynamic stresses. One of the shortcomings of conventional shaped bars is the fact that as the amperage level of the nominal currents to be carried rises, the constructive structure of the bars is considerably modified; this in particular leads to the need to correspondingly modify the supporting and/or insulation elements that couple to the bars. Moreover, coupling between bars is provided by means of conventional devices, for example connecting devices, which require the use of fixing means, typically T-shaped bolts. Said screws have a shaped head which, during assembly, is inserted in one of the slots of the bar and geometrically couples to the walls of said slot; however, this operation is difficult, because the screw does not stay in position but tends to fall, and therefore requires particular care on the part of the operator. In order to obviate this drawback, the solution used most commonly in the art is to associate with the head of the screw an adapted spring, for example a leaf spring, which is welded onto the head or otherwise locked onto the screw; although this solution is effective for the screw-bar coupling, it is disadvantageous because it requires an additional constructive component and has a negative effect on costs.
The aim of the present invention is to provide a bus bar for electrical power distribution whose structure has a modular geometry in which the basic geometric element can be easily adopted with bars sized for nominal currents of different amperage, for example 400A rather than 1600A, without significantly modifying the steps of the production of the bars or of the insulating and/or supporting elements that will be coupled to them, thus allowing advantageous economies of scale.
Within the scope of this aim, an object of the present invention is to provide a bus bar for electric power distribution whose constructive structure allows extreme flexibility and ease of execution in assembly.
Another object of the present invention is to provide a bus bar for electric power distribution whose structure is provided by using an optimum amount of material and at the same time has the rigidity sufficient to withstand the electrodynamic stresses to which it is subjected during normal operation.
Another object of the present invention is to provide a bus bar for electric power distribution which is highly reliable, relatively easy to manufacture and at competitive costs.
This aim, these objects and others which will become apparent hereinafter are achieved by a bus bar for electric power distribution, comprising a body made of conducting material, characterized in that said body has, on at least one side, at least one slot having a C-shaped cross-section, the back wall of said C-shaped slot comprising two substantially straight portions which form an angle of less than 180xc2x0 between them.
The bus bar according to the invention has the advantage of having a structure with a modular geometry whose basic geometric element is suitable to be easily implemented in the production of bus bars sized for nominal currents of different amperage, for example 400 A, 600 A, 1000 A, 1600 A or others, without significantly modifying the steps of the production of the bars or of the supporting and/or insulation elements to which said bus bars couple.